The Nest and Habits of the Connecticut Warbler in Minnesota
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VoL1929 XLVII I HUFF,Nest and Habits ofConnecticut Warbler. 455 THE NEST AND HABITS OF THE CONNECTICUT WARBLER IN MINNESOTA. BY N. L. HUFF. Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 Plates XXV-XXVI. ThE ConnecticutWarbler (Oporornisagilis) is one of the rarest of our songbirds. It was first collectedby AlexanderWilson in Connecticut,and notes concerningit were publishedin 1812.• It is seen not infrequently during migration seasons,mainly restrictedto the Mississippiriver valley in springand occasionally beyond,and to the Atlantic slopein autumn, but comparatively little is known or has been publishedof its home life and habits. For more than seventy years after the bird was described,its summer home was shroudedin mystery, and not until 1883 was the mystery partly cleared,when Ernest T. Seton•' discoveredthe first nest in a cold boggy tamarack swamp in Manitoba. He made no extensivestudy of the habits of the bird, and so the domesticlife of this rare songsterwas left in obscurity. Other records of its summer residenceare few, and the nest to be de- scribedin this paper is probably the first ever discoveredwithin the bounds of the United States, certainly the first recorded from Minnesota. 0. B. Warrens collectedyoung Connecticut Warblers in early August, 1894, in Marquette County, Michigan. Norman A. Wood4 reportsthe takingof an adult and youngon July 27, 1904, in OntonagonCounty, Michigan, and 0. M. Bryens5 reports maturebirds seen July 23, 1922, August18, 1923, and August 22, 1924, in Luce County, Michigan. These summerrecords, especiallyof immaturebirds, may be taken as goodevidence of breedingin the upper peninsulaof Michigan. It hasbeen known for manyyears that the ConnecticutWarbler is a summer resident of northern Minnesota. B.T. Gault ø saw Amer. Ornlth., ¾, 1812. Auk, I, 1884, 192. Auk, XII, 1895, 192. Auk, XXII, 1905, 178. Auk, XLII, 1925, 451. Auk, XI¾, 1897, 222. 456 •v•, Nestand Habits of Connecticut Warbler. [Oct.Auk one and heard severalothers singing in a swampin Aitkin County on June 21, and days following,1890. Dr. Thos. S. Roberts and L. L. L6fstr6m• saw adults,one a femalewith bill full of food, on June 20, 1915,in a swampin Isanti County, and Mr. L6fstrSm considered the bird as "a common summer resident of these Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 tamarack and sprucebogs." AlthoughI have visited the Isanti County bogs referred to, each June and July for the past five years, I have neither heard nor seen the Connecticut Warbler there, and it is bdievedthey have left the swampsof this county permanentlyfor the wilder regionsin the northern part of the State, or in Canada. My searchfor the nest of the ConnecticutWarbler began severalyears ago, as a result of a suggestionfrom Dr. Thos. S. Roberts,whose interest, enthusiasm, and personalityhave always beena stimulusfor more intensivestudy of bird life. It was on July 13, 1925, that I made my acquaintancewith the bird in its summer home. On this date I was driving through St. Louis Countyand whilepassing a spruceswamp some miles from Tower, I heard an unfamiliar bird songcoming from the depthsof the swamp. I enteredthe swampand in a few momentshad located the tamarack tree where the singerwas perched. In spite of the fact that the tree was small and its foliage sparse,it was an hour before I was able to get an unobstructedview of the bird that enabledme to identify him definitelyas the ConnecticutWarbler. During this time he was forcedto changehis locationtwo or three times but each time he eluded his observer and concealed himself in his new station beforerenewing his song. The song of the Connecticut Warbler varies with different individuals, and at times with the same individual. The volume may be changed,and certainsyllables may be changedor omitted, but the quality of his tone is unique and practicallyinvariable, especiallyas regardstwo syllables,"freecher," always included in his song. So characteristicis his voice that one having heard him may identify him more quickly by his songthan by sight. His voiceis sharp,piercing, penetrating, rather shrillyet pleasing, and is onethat I alwaysassociate with the wild swampywilderness where he sings. As with many other birds it is impossibleto Auk, XXXlI, 1915, 504. T•r Av•,VoL. XLVI. P•s•. XXV. Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 UPPER.--NEsT ANDEoas OF CONNECTICUTWARBLER (O•orornis agilis). LOWER.--NES? SITE IN SI•HAGNUM ANY LABRADOR TEA. Vol.•929 XLVI] I I-Iul•,Nest and Habits of Connecticut Warbler. 457 expressit with words, but his most common song suggeststhe syllables,freechef-here freechef-here freechef-here freech. Occa- sionallyI have heardthe song,freechef freechef freechef, resembling somewhat that of the Ovenbird, but often followed by other Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 notes, and so different in quality that one would never confuse the two. Frequently only a fractional part of either song is voiced. In his summer home the ConnecticutWarbler is a shy and elusivebird, so secretivein his manner that he would rarely be seenhere, even by those looking for him, were it not for his be- traying song. As we near his territory we hear his clear,ringing, unmistakablevoice. Onemay easilyapproach the treefrom which he poursforth his jubilant song,for he seemsto singwith even greatervigor as we near him; but to seehim may requirea long wait, and the closestscrutiny of every part of the tree's crown. His voice has somethingof a ventriloquial quality. As one circlesslowly about the tree from which he sings,the songmay apparently comefrom the lower branches,five or six feet from the ground,while in reality the singeris situatedthirty feet or more above. He continuesto singwith vigor, but his olive greenback and yellowishunder parts blend with the leaves,and he cautious- ly keepsa branch or a small massof foliagealways between him and his would-behuman observer. The art of concealinghimself behind a relatively small obstruction,is one which he has devel- opedto a degreeapproaching perfection. Little wonderthe records of his summer life are so few. Whendriven from his song perch by too closeapproach of hisob- serverhe escapes,often unseen, from the opposite side of the tree,and the first indicationof hisdeparture maybe his jubilant, triumphant songgushing from a tree severalyards away. If one is fortunate enoughto seehim enter another tree nearby, one is impressed with the remarkablefacility with which he creeps,half hidden, throughthe tree until he reachesa secureposition, separated from his observerby a limb or a smallmass of foliage. More than once as he scamperedalong a branch,his bodylow, his headextended, seekinga suitablehiding place, I have seenhim pausean inch be- yond the covetedspot. With headand shouldersvisible he takesa hastypeep at hisobserver, then suddenly retreats a stepor two and [Auk 458 HUFF,Nest and Habitsof ConnecticutWarbler. [Oct. adjustshis positionuntil he is wholly obscured.Here, frequently on a relativelylarge branch not far from the trunk of the tree, he at oncebegins his oft repeatedsong, freecher-here freecher-here free- cher-herefreech.Whether this is a loveditty to hismate, a warning Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 to other membersof his tribe that this territory is occupied,or simplyan uncontrolledoutburst of the exuberantjoy of living, who can say? Whatever his motive, he seemsquite oblivious to the presenceof a humanobserver so long as his form is hiddenamong the branches. If one remainperfectly still or in hiding for a while, the singer forgetsone's presence and sooner or later will moveout of hishiding place,walking along on a limb or occasionallyhopping to a nearby branch,taking some tiny insector othertidbit that meetshis fancy, all the while repeatinghis songseveral times each minute. His rel- ative inactivity, his rather slow deliberatemovements, now afford an excellentopportunity for observation. On June 6, 1926, on June 4, 1927, and again on June 3, 1928, while on botanicalexcursions through northern Minnesota, I heard or saw,on eachoccasion, Connecticut Warblers in certainswamps of Airkin County. Of theseswamps, one was selectedas the most promisingplace for observationof the habits,and the possibleloca- tion of a nest of this bird. This swampis perhapshalf or three- quartersof a mile wide and two miles or more in length. Much of its area is coveredwith a pure stand of small black spruce,some parts with an equallypure standof tamarack,but in placesthese two speciesare more or lessmixed together. The pitcher plant and the sundewthrive here, as do the buckbeanand the wild calla, the coralroot, the moccasinflower, and that rare and gorgeousor- chid, the dragon'smouth (Arethusabulbosa). In the Canadianswamp where Seton2 found the Connecticut Warbler nesting,he speaksof the songof this bird being the only noticeablesound save that of the Great CrestedFlycatcher. How differentthis Aitkin County swampl Here on a clear morningin Junethe air is filledwith bird voices. One hearsthe Hermit Thrush, the Willow Thrush, the SongSparrow and the White-throat, the Maryland Yellow-throat,BlackburnJan and PalmWarblers, four or five Flycatchers,Chickadees, Juncos, and several others, to say nothingof songsof the ScarletTanager, Rose-breasted Grosbeak, VoL1929 XLVI] ] HUFF,Nesi and Itabits of Conneciicui Warbler 459 Oven-bird,and Vireos that drift in from the bordersof the swamp. It is a placeattractive alike for the studentof plant life and the lover of birds. Recent explorations(1929) of only a part of this swamprevealed Connecticut Warblers singing in no lessthan five differentlocalities, and there are probablyseveral more than that Downloaded from https://academic.oup.com/auk/article/46/4/455/5256472 by guest on 30 September 2021 in the entire swamp.